[GHC] #10843: Allow do blocks without dollar signs as arguments

[GHC]

#10843: Allow do blocks without dollar signs as arguments
-------------------------------------+-------------------------------------
        Reporter:  agibiansky        |                   Owner:  agibiansky
            Type:  feature request   |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.2
  (Parser)                           |
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by agibiansky):

 @goldfire: The GHC parser (when I cloned master) had 48 shift/reduce
 conflicts, and this change introduces no new ones (there are still 48).
 (Actually I just went back to master and recompiled and checked, because I
 didn't check back when I cloned.) Anyway, this patch introduces no new
 shift/reduce conflicts.

 The code

 {{{
 main = - do
   putStrLn "Hello"
 }}}

 causes a parse error with my patch as before, with or without -XArgumentDo
 enabled.

 {{{
 parse error on input do
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10843#comment:9>
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